Twig Science Grade 7 (2021)

Molecule Builder

Create molecules using building blocks of carbon, hydrogen, oxygen, nitrogen, and other elements. Connect atoms by bonds, then create double or triple bonds if desired. For each completed molecule, write the chemical formula and, if the molecule is included in the database, observe the 3D structure. Create a variety of challenge molecules including cyclic molecules and isomers. 5 Minute Preview

Phase Changes

Explore the relationship between molecular motion, temperature, and phase changes. Compare the molecular structure of solids, liquids, and gases. Graph temperature changes as ice is melted and water is boiled. Find the effect of altitude on phase changes. The starting temperature, ice volume, altitude, and rate of heating or cooling can be adjusted. 5 Minute Preview

Phases of Water

Heat or cool a container of water and observe the phase changes that take place. Use a magnifying glass to observe water molecules as a solid, liquid, or gas. Compare the volumes of the three phases of water. 5 Minute Preview

Plate Tectonics

Move the Earth's crust at various locations to observe the effects of the motion of the tectonic plates, including volcanic eruptions. Information about each of the major types of plate boundaries is shown, along with their locations on Earth. 5 Minute Preview

Building Pangaea

In 1915, Alfred Wegener proposed that all of Earth's continents were once joined in an ancient supercontinent he called Pangaea. Wegener's idea of moving continents led to the modern theory of plate tectonics. Create your own version of Pangaea by fitting Earth's landmasses together like puzzle pieces. Use evidence from fossils, rocks, and glaciers to refine your map. 5 Minute Preview

Erosion Rates

Explore erosion in a simulated 3D environment. Observe how the landscape evolves over time as it is shaped by the forces of flowing water. Vary the initial landscape, rock type, precipitation amount, average temperature, and vegetation and measure how each variable affects the rate of erosion and resulting landscape features. 5 Minute Preview

River Erosion

Explore how river erosion affects landscapes in the short term and over long periods of time. Describe the features of mountain streams and meandering rivers, and use a floating barrel to estimate current speed. Witness the changes that occur as mountain streams erode downward and meandering rivers erode from side to side. 5 Minute Preview

Weathering

Weathering is the breakdown of rock at Earth's surface through physical or chemical means. Students will learn about the different types of mechanical and chemical weathering, then use a simulation to model the effects of weathering on different types of rocks in varying climate conditions. 5 Minute Preview

Chemical Changes

Chemical changes result in the formation of new substances. But how can you tell if a chemical change has occurred? Explore this question by observing and measuring a variety of chemical reactions. Along the way you will learn about chemical equations, acids and bases, exothermic and endothermic reactions, and conservation of matter. 5 Minute Preview

Chemical and Physical Changes - Middle School

The Secret Service recently arrested suspects accused of counterfeiting coins from 1915 valued at $50,000 each. The students act as a forensic scientist to investigate the crime scene and the evidence. Students learn about chemical and physical changes to recreate the methods used to make the coins as evidence for the trial. Video Preview

Feel the Heat

Have you ever used a glove warmer to keep your hands warm? How about an instant cold pack to treat an injury? In the Feel the Heat Gizmo, create your own hot and cold packs using various salts dissolved in water and different bag materials. Learn about exothermic and endothermic processes and how energy is absorbed or released when bonds are broken and new bonds form. 5 Minute Preview

Cell Energy Cycle

Explore the processes of photosynthesis and respiration that occur within plant and animal cells. The cyclical nature of the two processes can be constructed visually, and the simplified photosynthesis and respiration formulae can be balanced. 5 Minute Preview

Photosynthesis Lab

Study photosynthesis in a variety of conditions. Oxygen production is used to measure the rate of photosynthesis. Light intensity, carbon dioxide levels, temperature, and wavelength of light can all be varied. Determine which conditions are ideal for photosynthesis, and understand how limiting factors affect oxygen production. 5 Minute Preview

Coral Reefs 1 - Abiotic Factors

Explore the abiotic factors that affect Caribbean coral reefs. Many factors can be manipulated in this simplified reef model, including ocean temperature and pH, storm severity, and input of excess sediments and nutrients from logging, sewage, and agriculture. Click "Advance year" to see how the reef responds to these changes. 5 Minute Preview

Coral Reefs 2 - Biotic Factors

In this followup to the Coral Reefs 1 - Abiotic Factors activity, investigate the impacts of fishing, disease, and invasive species on a model Caribbean coral reef. Many variables can be manipulated, included intensity of fishing, presence of black band and white band disease, and the presence of actual and potential invasive species. Click "Advance year" to see the impacts of these biotic changes. 5 Minute Preview

Ecosystems - Middle School

As a national park ranger, students must restore the ecosystem of a park back to normal. They interact with populations of many organisms including wolves, deer and bees. Students learn the importance of food chains and webs, and how human factors can impact the health of an environment. Video Preview

Fruit Production - Middle School

As an agricultural scientist, students help a strawberry farmer who is having problems with low fruit production. Students learn about the factors involved in fruit production including plant nutrients, pollination and bees, and the interaction with the environment. Video Preview

Pond Ecosystem

Measure the temperature and oxygen content of a pond over the course of a day. Then go fishing to see what types of fish live in the pond. Many different ponds can be investigated to determine the influence of time, temperature, and farms on oxygen levels. 5 Minute Preview

Prairie Ecosystem

Observe the populations of grass, prairie dogs, ferrets and foxes in a prairie ecosystem. Investigate feeding relationships and determine the food chain. Bar graphs and line graphs show changes in populations over time. 5 Minute Preview