7th grade Science practice sheet
Alaska content standards · from Gradelings · Name: ______________________
Question 1
Which statement about compounds is true?
- Every compound contains a metal
- A compound always has the same elements in the same proportions
- A compound can have a different recipe each time it forms
- A compound has only one kind of atom
A compound always has the same elements in the same proportions
Hint: Water is always 2 hydrogen atoms to 1 oxygen atom, whether it's in a lake or a glass.
Question 2
When snowshoe hare numbers rise, lynx numbers usually…
- rise first, then the hares rise
- stay exactly the same
- fall at the same time
- rise a little later, because there is more food
rise a little later, because there is more food
Hint: Predator numbers follow prey numbers, with a delay. Records of the two populations rise and fall in linked cycles.
Question 3
Grass stores 5000 units of energy. About 10% of the energy at each feeding level is passed on to the next. How many units reach the frogs that eat the grasshoppers?
answer boxunits
50 units
Hint: Two steps: grass to grasshoppers (divide by 10), then grasshoppers to frogs (divide by 10 again).
Question 4
Put the steps of the water cycle in order.
- 🌊Water runs off or soaks in and collects in lakes and oceans
- ☁️Water vapor cools and condenses into clouds
- ♨️Water evaporates from lakes and oceans
- 🌧️Rain or snow falls
Water evaporates from lakes and oceans → Water vapor cools and condenses into clouds → Rain or snow falls → Water runs off or soaks in and collects in lakes and oceans
Hint: Water evaporates, condenses into clouds, falls as precipitation and then collects, ready to evaporate again.
Question 5
Cooking oil and water do not stay mixed. Both are pure, but together they form…
- a homogeneous mixture
- a single element
- a heterogeneous mixture
- a new pure substance
a heterogeneous mixture
Hint: Oil floats in a separate layer, so different parts are visible.
Question 6
What is the main job of a flower's bright petals?
- To hold the plant in the soil
- To take in water
- To make sugar for the plant
- To attract pollinators such as bees
To attract pollinators such as bees
Hint: Color and scent bring insects close to the flower.
Question 7
Substances made by a reaction are…
- reactants
- elements only
- products
- mixtures only
products
Hint: They are produced.
Question 8
Plates move about as fast as…
- your fingernails grow
- a car on a highway
- a running cheetah
- a falling rock
your fingernails grow
Hint: A few centimeters a year.
Question 9
How could you separate sand from water?
🏖️- add more water
- stir it faster
- use a magnet
- pour it through a filter
pour it through a filter
Hint: A filter lets water pass through but traps the bigger sand grains.
Question 10
What happens to a liquid that is cooled enough?
- It evaporates
- It freezes into a solid
- It melts
It freezes into a solid
Hint: Slower particles can lock into place.
Answer key
- 1. A compound always has the same elements in the same proportions (Atoms & Elements)
- 2. rise a little later, because there is more food (Ecosystems)
- 3. 50 units (Food Chains & Energy)
- 4. Water evaporates from lakes and oceans → Water vapor cools and condenses into clouds → Rain or snow falls → Water runs off or soaks in and collects in lakes and oceans (Cycles & Succession)
- 5. a heterogeneous mixture (Particles & Mixtures)
- 6. To attract pollinators such as bees (How Plants Work)
- 7. products (Chemical Reactions)
- 8. your fingernails grow (Earth's Moving Surface)
- 9. pour it through a filter (Mixtures & Solutions)
- 10. It freezes into a solid (Particles and Heat)
Want more than 10 questions?
In Gradelings the questions change every time and adjust to your child, with hints and kind feedback. See all science units.