8th grade Science practice sheet
Arizona Academic Standards · from Gradelings · Name: ______________________
Question 1
A hand warmer gets hot because of an…
- exothermic reaction
- electric shock
- physical change only
- endothermic reaction
exothermic reaction
Hint: Iron reacting with oxygen.
Question 2
Mechanical mixture or solution? Tap an item, then tap its basket.
Sort into: 🥣 mechanical mixture · 🧪 solution
- 🍪chocolate chip cookie
- 🎺brass (copper and zinc)
- 🥜trail mix
- 🥤fizzy water
- 🥗salad
- 🌬️air
🥣 mechanical mixture: chocolate chip cookie, trail mix, salad · 🧪 solution: brass (copper and zinc), fizzy water, air
Hint: In a mechanical mixture you can see the different parts. In a solution, one substance dissolves into another, so it looks the same all the way through.
Question 3
Pure substance or mixture? Sort each one.
Sort into: 💎 pure substance · 🥣 mixture
- 🍲vegetable soup
- 🌬️air
- 🟡a gold bar
- 🟠a copper wire
- 🥜trail mix
- 💧distilled water
- 🌊salt water
- 🧂pure table salt
💎 pure substance: a gold bar, a copper wire, distilled water, pure table salt · 🥣 mixture: vegetable soup, air, trail mix, salt water
Hint: A pure substance is one kind of matter (an element like gold, or a compound like water). A mixture is two or more substances physically combined.
Question 4
A force of 20 N does 140 J of work. How far, in m, did the object move?
answer boxm
7 m
Hint: Displacement = work ÷ force.
Question 5
A mirror shows your image because light…
- disappears
- reflects off it
- bends through it
- is absorbed
reflects off it
Hint: Reflection is when light bounces off a surface.
Question 6
Selective breeding is when…
- animals choose by weather
- nature chooses randomly
- traits are made from nothing
- people choose parents with desired traits
people choose parents with desired traits
Hint: Dog breeds, crops.
Question 7
Organisms usually produce more offspring than can survive. This leads to…
- competition for resources
- identical offspring
- no predators
- unlimited food
competition for resources
Hint: Not everyone gets enough.
Question 8
Earth is about how old?
- 6000 years
- 100 years
- 1 million years
- 4.6 billion years
4.6 billion years
Hint: Very old.
Question 9
Scientists forecast monsoon storms using…
- coin flips
- radar, satellites and weather data
- the shape of clouds alone
radar, satellites and weather data
Hint: Better forecasts give people time to prepare.
Question 10
An endothermic reaction…
- makes light only
- absorbs thermal energy
- releases thermal energy
- has no products
absorbs thermal energy
Hint: Endo = in.
Answer key
- 1. exothermic reaction (Chemical Reactions)
- 2. 🥣 mechanical mixture: chocolate chip cookie, trail mix, salad · 🧪 solution: brass (copper and zinc), fizzy water, air (Mixtures & Solutions)
- 3. 💎 pure substance: a gold bar, a copper wire, distilled water, pure table salt · 🥣 mixture: vegetable soup, air, trail mix, salt water (Particles & Mixtures)
- 4. 7 m (Work, Energy & Efficiency)
- 5. reflects off it (Light & Radiation)
- 6. people choose parents with desired traits (Genes & Heredity)
- 7. competition for resources (Natural Selection)
- 8. 4.6 billion years (Earth's History & Fossils)
- 9. radar, satellites and weather data (Resources & Hazards)
- 10. absorbs thermal energy (Chemical Reactions)
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.